BHET-PHB热致液晶聚合物的合成及表征

以对苯二甲酸乙二醇酯（BHET）和对羟基苯甲酸（PHB）为原料，采用熔融缩聚法合成了BHET－PHB热致液晶共聚酯。合成的共聚酯化学结构通过红外和核磁来验证，并用DSC、偏光显微镜和X射线衍射研究了其液晶行为，证明BHET－PHB共聚酯为典型的向列型液晶。     

PBT/PHB热致液晶共聚酯的原位乙酰化合成与表征

采用原位乙酰化法，合成了对羟基苯甲酸(PHB)摩尔分数不同的PBT／PHB共聚酯，研究了其组成与相转变和液晶性之间的关系。结果表明，采用PHB的原位乙酰法合成的PBT／PHB共聚酯，当PHB刚性基元的摩尔分数为为20％～80％时，PBT／PHB共聚酯为向列型热致性液晶，并存在明显的双玻璃化现象；当PHB的摩尔分数达到50％后，共聚酯表现出两个熔点。这种多重相转变与PBT／PHB共聚酯中存在不同程度的富PBT相和富PHB相有关。采用PHB的原位乙酰化法代替乙酰氧基苯甲酸的酯交换法，一定程度上抑制了PHB嵌段链的形成。     

PBT／PHB热致液晶共聚酯的原位乙酰化合成与表征

采用原位乙酰化法，合成了对羟基苯甲酸(PHB)摩尔分数不同的PBT／PHB共聚酯，研究了其组成与相转变和液晶性之间的关系。结果表明，采用PHB的原位乙酰法合成的PBT／PHB共聚酯，当PHB刚性基元的摩尔分数为20％～80%时，PBT／PHB共聚酯为向列型热致性液晶，并存在明显的双玻璃化现象；当PHB的摩尔分数达到60％后，共聚酯表现出两个熔点。这种多重相转变与PBT／PHB共聚酯中存在不同程度的富PBT相和富PHB相有关。采用PHB的原位乙酰化法代替乙酰氧基苯甲酸的酯交换法，一定程度上抑制了PHB嵌段链的形成。     

PBT-PHB热致性液晶共聚酯的合成研究

以对羟基苯甲酸甲酯和1,4-丁二醇为原料,在稳定剂、催化剂存在条件下,合成双-对羟基苯甲酸丁二酯（BBHB）;以对苯二甲酸二甲酯和1,4-丁二醇为原料,合成对苯二甲酸二丁二酯（DBT）;采用熔融缩聚法由BBHB和DBT合成含柔性间隔基的液晶共聚酯PBT—PHB。由正交实验确定最佳反应条件和实验配方。用带有偏光显微镜的熔点仪、傅立叶红外光谱仪分别测定熔点、液晶温度范围和结构,并利用粘度与粘均相对分子质量间的对应关系计算出该液晶共聚酯的粘均相对分子质量。     

热致液晶共聚酯60PHB/PEN的合成及其表征

合成了对乙酰氧基苯甲酸与聚萘二甲酸乙二醇酯的热致液晶共聚酯(简称60PHB/PEN)。通过元素分析、红外光谱、DSC、热台偏光显微镜以及广角X射线衍射对其进行了结构、液晶性表征。实验表明,合成的共聚酯确系高度无规的PEN、PHB共聚酯,在某个温度范围内呈现向列型液晶的典型特征。     

热致液晶性PHB／PET共聚酯的热性能

以对羟基苯甲酸(PHB)和聚对苯二甲酸乙二酯(PET)为原料,经熔融缩聚制备了一系列不同配比的液晶性PHB/PET共聚酯;并研究了这些共聚酯的热转变行为和热稳定性。结果丧明:20PHB/PET共聚酯的冷结晶温度比PET高,而结晶温度比PET低,表明PHB/PET在未形成液晶相的情况下,少量PHB的刚性链段阻碍了PET链节的运动,使其比纯PET更难结晶;在空气介质中,共聚酯的第一热分解温度均高于380℃。PHB含量少于80mol%时,第一热分解温度变化不大,多于80mol%时则迅速上升;第二热分解温度均高于490℃,且随PHB含量增加而呈直线上升。     

芳香酯基液晶环氧树脂的合成

以对羟基苯甲酸和对苯二酚为原料,用对甲苯磺酸共沸催化法合成对羟基苯甲酸对苯二酚酯;再由对羟基苯甲酸对苯二酚酯与4-溴环氧丁烷进行反应合成酚酯型液晶环氧物质4-(2-(环氧乙烷基)乙氧基)苯甲酸-4-(2-(环氧乙烷基)乙氧基)苯酚酯。研究该化合物与4,4’-二氨基二苯甲烷(DDM)固化反应的固化特性及固化物的力学性能,并对其结构以及固化行为和固化物的形态进行了表征。结果表明该液晶环氧树脂与DDM交联聚合的网络保持了较好的液晶织态,聚合物具有较好的综合性能。     

含芳酯基液晶基元环氧树脂的合成与表征

本文以对羟基苯甲酸和对苯二酚为原料,用浓硫酸—硼酸共沸催化法合成对羟基苯甲酸对苯二酚酯;再用其与环氧氯丙烷进行反应合成酚酯型液晶环氧——4,4’-对羟基苯甲酸对苯二酚二缩水甘油醚(PHBHQ)。研究了合成工艺、反应条件、提纯方法等因素对产率的影响,找出了一套合理的合成方案来合成液晶环氧。最后用傅立叶变换红外光谱(FTIR)、显微熔点测定仪测量熔点、元素分析等方法对产物结构进行了表征。     

PET／60PABA 热致型液晶共聚酯的合成与表征

将对羟基苯甲酸（PHB）的乙酰化产物对乙酰氧基苯甲酸（PABA）引入聚酯（PET）分子主链结构中,成功制备出共聚酯 PET /60PABA,研究了聚合温度和催化剂浓度对共聚酯合成的影响。通过差示扫描量热（DSC）、X 射线衍射（XRD）、超导核磁共振（NMR）、凝胶渗透色谱（GPC）、偏光显微镜（POM）和毛细管流变仪等手段对共聚酯的分子结构与液晶形态进行表征,结果表明,共聚酯 PET /60PABA 几乎为完全无规共聚,熔融状态下具有向列型热致液晶聚合物的典型特征。     

热致性液晶聚氨酯的合成及表征

首先制备液晶基元,以对羟基苯甲酸甲酯和1,4-丁二醇为原料,钛酸四正丁酯为催化剂,通过熔融酯交换反应合成了液晶基元双(对羟基苯甲酸)丁二醇酯.对反应的最佳条件进行了考察得出结论:在对羟基苯甲酸甲醑为15.5 g,1,4-丁二醇为4.4 mL,钛酸四正丁酯为2.5 mL,反应温度为160℃时,反应进行的较完全,分出甲醇的量接近理论值4 mL.对所得的液晶基元的DSC及POM分析表明,该液晶基元没有液晶性.然后,将液晶基元与对苯二甲酰氯反应制得对苯二甲酰氯苯甲酸丁二醇酯(PHTO),将对苯二甲酰氯苯甲酸丁二醇酯(PHTO)与2,4-甲苯二异氰酸酯(2,4-TDI)反应制得液晶聚氨酯.用差热扫描量热分析仪(DSC)、偏光显微镜(POM)对产物的熔点和清亮点、液晶性进行表征.结果表明:合成的聚氨酯产物在202℃(熔点)和261℃(清亮点)之间为热致性向列型液晶.     

向列型含氟侧链高分子液晶的合成与表征

合成了4-(丙烯酸乙氧基酯)苯甲酸,4-(丙烯酸乙氧基酯)苯甲酰氧基苯甲酸等系列液晶中间体.首次合成了4-(丙烯酸乙氧基酯)苯甲酰氧基苯甲酸基元的含氟侧链高分子液晶,采用IR,1HNMR和19FNMR表征了其分子结构.通过DSC分析和偏光显微镜研究了含氟侧链高分子液晶的织构形态.结果表明,4-(丙烯酸乙氧基酯)苯甲酰氧基苯甲酸基元含氟侧链高分子液晶具有向列型液晶的织构形态.4-(丙烯酸乙氧基酯)苯甲酰氧基苯甲酸基元含氟侧链高分子液晶,其液晶温度范围较宽,随着液晶基元成分的降低,含氟侧链成分的增加,高分子液晶玻璃化温度略有降低.     

热致性液晶共聚酯／聚丙烯共混物

通过熔融共混制备了不同配比的（ＰＨＢ／ＰＥＴ）／ＰＰ共混物，研究表明，共混物的弯曲弹性模量，弯曲强度及拉伸强度均比ＰＰ有所提高，当液晶含量为１５％，ＰＰ－ｇ－ＭＡＨ为２０％时，（ＰＨＢ／ＰＥＴ）（ＰＰ－ｇ－ＭＡＨ）／ＰＰ三元共混物弯曲弹性模量最大，ＰＰ－ｇ－ＭＡＨ作为两相界面相容剂，改善了两相间的亲合性。ＤＳＣ分析表明，共混物中ＰＰ相的结晶温度有较大幅度的提高，（ＰＨＢ／ＰＥＴ）共聚酯起了ＰＰ结晶     

以甲基三氯硅烷为中心的液晶分子的合成与表征

用对羟基苯甲醛、对硝基苯胺合成了席夫碱化合物,然后与氯乙醇发生取代反应,最后接到甲基三氯硅烷上合成新的液晶化合物。通过红外光谱对液晶化合物的结构进行表征,利用DSC和偏光显微镜测试目标产物的液晶性能。结果表明,此液晶化合物具有近晶型液晶特性,液晶相变温度范围较宽(205~251℃),为液晶小分子的发展提供了新的方向。     

Effect of side chain structure of polyimides on a pretilt angle of liquid crystal cells

A series of poly(amic acid)s had been synthesized from cyclobutane-1,2,3,4-tetracarboxylic dianhydride (CBDA) and 4,4′-diaminodiphenyl methane (DDM) and functional diamines with various side chain structures. The functional diamines, like 3,5-diamino benzoic acid hexadecane-1-yl ester which had long alkyl or rigid alicyclic side chains with different flexibility had been synthesized. Pretilt angles of liquid crystal cell fabricated with the poly(amic acid)s were measured and investigated factors affecting on the pretilt angles. The pretilt angles of the liquid crystal on the polyimide (5a) with rigid side group was 0.6°, on the other hand, the pretilt angle on the polyimide (5b) and (5c) with flexible side chains were very high above 89.6°. Furthermore, the pretilt angle of liquid crystal on the polyimide (5c) film having rigid cylindrical structure with 6-methylheptyl at the chain end was still high above 86.0° even after the rubbing process.     

Synthesis and characterization of thermotropic liquid crystalline poly(ester‐imide‐ketone)

A series of poly(ester imide ketone)s derived from N,N′‐hexane‐1,6‐diylbis(trimellitimide), 4,4′‐dihydroxybenzophenone, and p‐hydroxybenzoic acid (PHB) were synthesized by the direct polycondensation method in benzene sulfonyl chloride, dimethylformamide, and pyridine with varied PHB contents. The liquid crystalline behavior and thermal properties of the poly(ester imide ketone)s were characterized by polarized‐light microscopy, wide‐angle X‐ray diffraction, thermogravimetric analysis, differential scanning calorimetry, and temperature‐modulated differential scanning calorimetry (MDSC). The results showed that the synthesized polymers possessed a nematic thermotropic liquid crystalline characteristic and high thermal stability. The liquid crystalline polymers, with a PHB content ranging from 0 to 50 mol %, exhibited multiple phase transitions as evidenced by the MDSC results. A transitional smectic phase from solid state to nematic thermotropic liquid crystalline state was observed, and a transition model is proposed. Under certain conditions, the polymer with 33 mol % PHB content showed two significantly different liquid crystalline textures. This type of liquid crystalline polymer exhibited excellent fiber forming. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1045–1052, 2003     

Morphological,thermal, rheological,and mechanical properties of PP/EVOH blends compatibilized with PP‐g‐IA

We prepared some blends of polypropylene (PP) and ethylene vinyl alcohol (EVOH) with and without a compatibilizer. As a new compatibilizer, we synthesized polypropylene grafted with itaconic acid (PP‐g‐IA) using Brabender mixing system. We investigated the morphological, thermal, rheological, and mechanical properties of a compatibilized blends (PP/EVOH/PP‐g‐IA) and not compatibilized blends (PP/EVOH). Our experiments showed that carboxylic acid groups in PP‐g‐IA and hydroxyl group in EVOH formed strong in situ hydrogen bond in the compatibilized blends, resulting in better morphological and mechanical properties of the compatibilized blends than those of not compatibilized blends. POLYM. ENG. SCI., 56:1240–1247, 2016. © 2016 Society of Plastics Engineers     

单酯基多环芳香酸的合成及热分析

以4-正丙基,4-正戊基取代的双环己基甲酸、联苯甲酸和环己基苯甲酸以及对羟基苯甲醛为原料,用一次酯化、一次氧化的方法(酯化氧化法),合成了4个单酯基芳香酸类化合物:4-〔4-(反-4-丙基环己基)苯酰氧基〕苯甲酸,4〔-反-4-(反-4-丙基环己基)环己酰氧基〕苯甲酸,4-〔反-4-(反-4-戊基环己基)环己酰氧基〕苯甲酸和4-〔4-(4-戊基苯基)苯酰氧基〕苯甲酸,总产率分别为74%,76%,72%和71%。产物结构用IR,MS,1HNMR及元素分析进行了表征,DSC及偏光显微镜测定表明,4个目标化合物具有热致液晶性。     

Preparation of chelating fabrics by radiation‐induced grafting of itaconic acid and acrylonitrile onto polypropylene nonwoven fabrics and subsequent amination of graft copolymer

A mixture of acrylonitrile (AN) and itaconic acid (IA) was cografted onto polypropylene (PP) nonwoven fabrics by preirradiation method. The effects of graft polymerization conditions such as temperature, reaction time, Mohr's salt concentration, solvent mixture ratio, and comonomer composition on the total grafting yield were investigated. The addition of AN as a comonomer increased the amount of IA that reacted with PP fabrics. An increase in the temperature from 40 to 60°C increased the grafting rate, but the final grafting yield decreased at high temperature. The addition of 0.01 wt % Mohr's salt to the reaction medium leaded to a sharp increase of grafting yield. The accelerative effect of solvent medium on the grating yield was higher in dimethylformamide (DMF) and methanol mixtures, when compared with DMF or methanol. Chelating fabrics was synthesized by subsequent amination of grafted fabric with ethylene diamine (EDA) and phenylhydrazine (PH). The conversion yield reached maximum value at about 90% for 80% PP‐g‐AN‐IA fabrics at 90°C. At same amination conditions, the conversion yield is higher when PP‐g‐AN‐IA fabrics react with EDA compared with PH. FT‐IR data indicate that amine groups were introduced onto PP‐g‐AN‐IA fabric through amide linkage between grafted AN or IA and EDA or PH. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

DCC法合成胆甾醇酯

研究以二环己基碳二亚胺(DCC)作脱水剂,分别用4-二甲胺基吡啶(DMAP)和N,N-二甲基苯胺作除水促进剂,胆甾醇与丙酸、苯甲酸在室温下反应合成液晶材料胆甾醇丙酸酯和胆甾醇苯甲酸酯的方法.该方法反应条件比较温和,用DMAP作除水促进剂时,胆甾醇酯产率比较高.发现用N,N-二甲基苯胺作除水促进剂也可以合成胆甾醇丙酸酯,这有利于降低胆甾醇丙酸酯合成成本,但合成胆甾醇苯甲酸酯时没有成功.